Battery operated communication devices are well known in the art. Such devices may comprise, for example, cellular telephones, personal digital assistants, or even laptop computers with wireless or wired connections to other resources, such as a communication network. As such devices have evolved, the quantity and quality of data that may be received and reproduced by such devices has dramatically increased. For example, it has very recently become common for current cellular telephones to be equipped with multi-media capability such that the cellular telephone can receive and decode various types of media streams such as audio, video, two-dimensional (2D) and three-dimensional (3D) graphics, etc.
With the increased capability of such devices, there's has been a commensurate increase in the power demands placed upon such devices. For example, in order to provide the greater functionality called for by multi-media applications, the amount of processing or computing power available in such devices has been commensurately increased. As a result, greater power consumption occurs. To address this situation, longer lasting batteries having greater storage capacity have been created. However, there are limits to the improvements available through battery technologies. Other techniques are necessary if devices are to be able to keep up with the power demands of ever more capable user applications.
Other techniques for reducing power supply consumption in devices are known, particularly for devices that perform encoding of various media types. For example, U.S. Pat. No. 6,493,326 discloses a technique which lowers the encoding rate of a variable rate voice coder in response to reduced voice activity by a user of the device. In this manner, the circuitry necessary to transmit the voice data is energized less frequently, thereby resulting in reduced power consumption. In a similar vein, Japanese Published Patent Application No. 2000-174696 teaches a system in which the voltage of a battery is monitored to determine when the voltage falls below a certain threshold. When this occurs, the rate of voice encoding is decreased, e.g. to half rate or less, such that the time required to transmit voice data is similarly decreased. Once again, power consumption of the device may be reduced. Further still, Published Japanese Patent Application No. 2000-069556 describes a system in which an encoding rate upper limit for a voice encoder is set by user of the device. When a power saving mode is entered, preferably through actuation of an input mechanism by a user of the device, the encoding rate of the voice encoder is limited by the previously established upper limit. Each of the above-described techniques limits power usage by reducing the rate of encoding activities performed by the device.
Silent on the problem of reducing power consumption in devices, U.S. Pat. No. 5,579,339 describes a system in which a communication unit (i.e., a device) can transmit a request to concurrently monitor multiple, digitally-encoded communications in a wireless communication system. To this end, a wireless network in communication with the unit provides interleaved, reduced rate communications to the communication unit. For example, in order to monitor two communication streams, the wireless network provides two communication streams, each encoded at half rate encoding levels. In this manner, devices are able to request reduced rate data streams from a communication network.
However, the prior art is silent with regard to techniques whereby devices may control the rate of received data streams in response to sensed power conditions. Therefore, it would be advantageous to provide techniques that overcome these limitations. It would be additionally advantageous for such techniques to be applicable to non-battery powered devices for which energy conservation is nevertheless an issue of concern.